1. Technical Field
The present invention relates to a liquid crystal display technical field; more particularly, to a method of manufacturing a thin film transistor and a method of an organic light emitting diode display.
2. Background Art
A flat panel display is widely applied for the advantages, such as thin body, low power consumption, etc., and the existing flat panel display generally includes a liquid crystal display (LCD) and an organic light emitting diode display (OLED).
The organic light emitting diode display is a self-luminous display device that displays an image through an organic light emitting diode. Different from the liquid crystal display (LCD), the organic light emitting diode display emits the light using the energy generated by excitons, which are generated by combining electron-hole in the organic emitting layer, from an excited state to a ground state, which does not need a separate light source accordingly, thereby having small thickness and weight. In addition, since the organic light emitting diode display presents a high quality character, such as, low power consumption, high lightness and short response time, which is eye-catching as a next generation display device of the portable electronic device.
A Thin Film Transistor (TFT) is generally used as a drive in the organic light emitting diode display, thereby realizing display screen information with high speed, high lightness and high contrast. In recent years, the thin film transistor of based on metal oxide is given more and more importance for the advantages, such as high mobility, good light transmission, stable thin film structure, low manufacture temperature and low cost, etc. Especially, the metal oxide TFT of In—Ga—Zn—O (IGZO) as the representative and the current a-Si TFT have relatively high manufacturing compatibility, which are hereby widely applied in manufacturing an OLED panel having a large size.
Referring to FIG. 1, a 2Tr-1Cap structure widely applied in the OLED of the prior art is illustrated, one organic light emitting diode 30, two thin film transistors 10 and 20 and a capacitor 40 are included in each of pixel regions. Wherein the first thin film transistor 10 provides a switch voltage for the second thin film transistor 20 as a switch, and the second thin film transistor 20 is used for providing a drive circuit for the organic light emitting diode 30. A first gate of the first thin film transistor 10 is connected to a scan line 510; a first source of the first thin film transistor 10 is connected to a data line 520; a first drain of the first thin film transistor 10 is connected to a second gate of the second thin film transistor 20, and meanwhile connected to a second source of the second thin film transistor 20 through the capacitor 40; a second source of the second thin film transistor 20 is connected to a common power supply line 530; a second drain of the second thin film transistor 20 is connected to an anode of the organic light emitting diode 30 for providing a drive circuit for the organic light emitting diode 30.
Referring to FIG. 2, a method of manufacturing a thin film transistor provided by the prior art is illustrated, wherein the depositing of the second thin film transistor 20 includes:
i) depositing a conductive layer on a substrate 210, depositing a photoresist layer on the conductive layer, and exposing and photoetching the photoresist layer simultaneously, thereby forming a first gate 121 of the first thin film transistor 10 and a second gate 221 of the second thin film transistor 20;
ii) depositing an insulating layer 230 above the substrate 210, the insulating layer 230 covers the first gate 121 and the second gate 221, depositing a photoresist layer above the insulating layer 230, and exposing and photoetching the photoresist layer simultaneously, thereby forming one first connection window 231 on the insulating layer 230 above the second gate 221;
iii) depositing an oxide semiconductor layer 240 above the insulating layer 230, depositing a photoresist layer above the oxide semiconductor layer 240, and exposing and photoetching the photoresist layer simultaneously, thereby forming a first active layer 141 of the first thin film transistor 10 and a second active layer 241 of the second thin film transistor 20; and
iv) depositing a second source 251 and a second drain 252 of the second thin film transistor 20 above the insulating layer 230 and the second active layer 241, and meanwhile depositing the first source 151 and the first drain 152 of the first thin film transistor 10 above the insulating layer 230 and the first active layer 141, wherein the first drain 152 is electrically connected to the second gate 221 through the first connection window 231.
The above process is subjected to be exposed for three times by a yellow light machine, such that the manufacture time increases, and the productivity is lowered, thereby increasing the manufacturing cost.